<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>事件代理</title>
  <style>
    .parent {
      height: 500px;
      background-color: powderblue;
      overflow: hidden;
    }
    .child {
      width: 100px;
      height: 100px;
      background-color: seagreen;
      margin: 50px;
      float: left;
    }
  </style>
  <script>
    window.onload = function() {
      // 1.获取dom节点
      var parent = document.getElementsByClassName('parent')[0]
      var child = document.getElementsByClassName('child')
      // 将类数组对象转成数组
      child = Array.prototype.slice.call(child)
      // 事件代理(底层逻辑：事件冒泡)
      parent.onclick = function(event) {
        // 判断当前点击是否为子元素
        if(event.target.className === 'child'){
          alert('子元素')
        }
      }


      // 动态添加dom节点
      var cloneDom = child[0].cloneNode(true)
      parent.appendChild(cloneDom)
    }
  </script>
</head>
<body>
  <div class="parent">
    <div class="child">one</div>
    <div class="child">two</div>
    <div class="child">three</div>
    <div class="child">four</div>
    <div class="child">five</div>
  </div>
</body>
</html>